1. Field Of The Invention
The invention relates to a transmitter station for transmitting a plurality of television programs via respective transmission channels, comprising a data generator adapted to transmit tuning data in the television signal of one of the television programs at a given repetition frequency, said tuning data being representative of the transmission channels used by the transmitter station. The invention also relates to a television receiver for receiving television signals from such a transmitter station.
Generally, television receivers are tuned to a desired program by means of preset keys, also referred to as program numbers or preset numbers. A tuning memory in the receiver comprises a tuning data for each preset number in the form of the transmitter frequency or channel number, by means of which the receiver is tuned to the corresponding transmission channel. When the receiver is used for the first time, the tuning memory is to be programmed in a procedure referred to as installation procedure. However, also when the installation procedure in a receiver has already been carried out, it may be desirable to modify allocated preset numbers, for example, when a new television program is introduced.
2. Description Of The Related Art
Various embodiments of the installation procedure are known. An attractive embodiment is described in European Patent Application EP 0 263 555, corresponding to U.S. Pat. No. 4,894,714. This procedure is notably applicable in cable television systems in which the cable network manager takes care of the distribution of television programs. As described in this Patent Application, the cable television transmitter station transmits, simultaneously with at least one of the television programs, a teletext page in which the tuning data of the available programs and corresponding preset numbers are stated. The relevant teletext page has a standardized page number, for example a hexadecimal page number outside the conventional range of 100-899. The installation procedure now comprises the selection of this page and the storage of the tuning data which it incorporated in the page in the tuning memory. Subsequently, all receivable programs can be called by means of the preset number determined by the manager. Generally, this number will satisfy the user's wishes.
The teletext page with tuning data is preferably transmitted with the television signal of a local television program generated by the cable network manager. Practically all cable networks transmit such a program in the form of a cable newspaper, a mosaic image or the like. However, it is not known in advance at which frequency or channel number the local television program is transmitted. As described in said European Patent Application, the television receiver therefore searches all channels in the installation procedure until the program of the predefined teletext page has been found. At each television program which has been found and which also transmits teletext (nowadays virtually all programs) a given waiting time needs to be observed to determine whether the teletext page with tuning data is available. The waiting time is relatively long because the page with tuning data may form part of a repetitive cycle comprising a plurality of teletext pages. In practice, a teletext cycle period, hence, the repetition time of the page with tuning data, may be more than 30 seconds. Consequently, a problem of the known installation procedure is that the installation may take many minutes. This detracts considerably from the potential user convenience of the known procedure.